Telephone-receiver.



Patented Aug'. 22, |899.

.1. A. WILLIAMS. TELEPHONE RECEIVER.

(Application filed Apr. 9, 1898.) (N o M n d e'l lllllll /NVE/VT'H a. ATTORNEYS jUNiTED STATES ATE'N' FFI@ if@ JOSEPH, IVILLIAMS, OF CLEVELAND, OHIO, ASSIGNOR TO THE XVILLIAMS ELECTRIC COMPANY, OF SAME PLACE.

TELEPHONE-RECEIVER.

SPECIFICATION forming part of Letters Patent No. 631,354, dated August 22, 1899.

Application l'led April 9, 1898. Serial No. 677,035. (No model.)

To all whom, it Guay concern:

' Be it known thatl I, JOSEPH A. WILLIAMS, o'f Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in Telephone-Receivers; and I do herebj7 declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which itl pertains to make and use the same. i

' My invention relates `Ato improvements in telephone-receivers.

The primary object of the invention is to so support the bobbin from the case and to so construct the bobbinand engaging magnet-pole that the space between the pole-tip and diaphragm shall not--beaffected by expansion and contraction ofthe case and magnet and that rough or careless handling of the instrument shall 'not affect the adjustment of the bobbin and its engaging magnetpole. j

With this object in view and to the end of attaining other advantages hereinafter speci-v fied and to render the instrument light, durable, and efcient my invention consists in certain features of construction and combinations of parts hereinafter described, and pointed out in the claims.

In the accompanying drawings, FigureI is a side View, mostly in longitudinal section, of an instrument embodying my invention. Fig. II is a longitudinal section on line II II, Fig. I. Fig; III is a transverse section on line III III, Fig. I. Fig. IV is a transverse section on line IV IV, Fig. I, looking in the direction of the arrow.V

Referring to the drawings, A designates the tubular orhollow case of the instrument,which case is preferably made of polished ebonite or vulcanized rubber in the usual manner.

B designates the permanent magnet,`that is suitably arranged within and longitudinally of the case A. The said magnet is in the case illustrated of the compound or laminated variety and is made up of five bars provided with iron poles B B2, partially embraced by opposite ends, respectively, of the central bar b of the magnet.

The case A at one end is provided with the binding-post bearing-head C and at its opposite end has the earpiece D. Pole-piece B', and consequently the magnet., is secured to head C by the screw C. The said polepece B/ is provided with an ear b',that extends between the four outer bars of the magnet and engages a recess b2, formed in the adjacent end of the magnets central bar, that therefore partially embraces thesaid ear widthwise of the said bar. A bolt E, that extends through the said ear and through the four outer bars of the magnet, together with a nut c, thatis mounted upon the threaded shank of the bolt, clamps the said bars of the magnet and ear together. The other pole of the magnet comprises, preferably, a bunch of softiron or magnetic wires Bthat are bent around a bolt F, employed in securing together the other ends of the bars of the magnet and that have `their ends crowded into but slidable endwise of the hollow hub or core G of the bobbin G, which core is composed of suitablymagnetic material--such, for instance, as soft iron-and forms a part of the magnetpole, comprising' the said wires, and constitutes the tip of the said pole. rl`he central bar of the magnet is recessed, as at b3, to accommodate its partially embracing the bend in-the said iron wires, as shown in Figs. I and II. The bolt F, around which the said wires are bent and that extends through the four outer bars of the magnet, and the nut f, that is mounted upon the threaded shank of the said bolt, hold the said wires and the magnet-bars together. It will be observed, therefore, that the central bar of the magnet is positively prevented from edgewise displacement laterally of the instrument by the members or portions of the pole-sections that are partially embraced by the said bar.

rlhe instruments earpiece is providedwith a centrally-located aperture d in the ordinary manner. d

Case A is enlarged diametrically in the usual manner at is bobbin-containing end, that is annular and provided externally with screw-threads engaged by the correspondingly internally threaded annular flange B of the earpiece, that at-the inner end of its ange and internally is provided with an annular shoulder d', arranged to hold in place against the adjacent end of case A the dia- IOO phragm I, that is arranged in suitable proximity to the pole-tip-forming portion of the bobbin. The bobbin is adj ustablc toward and from the diaphragm to accommodate the format-ion of the space required between the diaphragm and the tip of the adjacent magnet-pole, and the wire coil G2 of the bobbin is carefully insulated. The bobbin at its ends is provided with brass or non-magnetic heads g g, that to avoid eddy-currents are provided with any suitable number of radiallyarranged slots g', arranged, preferably, equidistant apart.

H designates the insulation between the coil and the heads and core of the bobbin and is indicated by heavy black lines. The bobbins inner head is diametrically larger than its outer head and is engaged at its edge by screws J, that support the bobbin and engage correspondingly-threaded holes a, formed in and longitudinally of case A. In the case illustrated fourscrewsJ are arranged at equal intervals circu inferentially of the bobbin, and each screw has two annular shoulders J/ J', arranged apart a distance equal to the thickness of the bobbins inner head that snugly fit, therefore, between the said shoulders, and the screws between the said shoulders snugly engage said head, that in its surrounding edge has slots g2, having arc-shaped walls that partially and snugly embrace the screws. By this construction the bobbin, and consequently the pole-tip that forms a part of the bobbin, cannot possibly become displaced independently of the supporting-screws neither endwise nor laterally nor circumferentially, and it is obvious that with the coil-embraced and bobbin-forming pole-tip and body portion of the pole shiftable endwise independently of each other and with the diaghragm and bobbin and pole-tip supported from the bobbin-containing end of the case no expansive or conti-active influence upon the case or upon the magnet can affect the relative l is within the bobbin-containing end of case A and abuts and forms an inward extension ot' the diaphragm I. The said shell does not,

bar-containing portion of the case. The said member I forms a partial return-path for the lines of magnetism and induces more lines to pass into and through the bobbin, if, as in the case illustrated, it does not extend inwardly too far. An extension ot` the said member I' inwardly beyond the inner end of the bobbin would be detrimental, because it would induce a shorter path for the magnetic lines from the bobbin-embraced pole to the opposite pole.

That I claim isl. In a telephone-receiver, the coil-bearing bobbin supported independently of the magnet and provided with a magnetic hub or core that forms the tip of the adjacent pole of the magnet, and the body portion of the said pole consisting of magnetic strands or wires hunched and shiftable within the aforesaid tip and suitably attached tothe adjacent portion of the magnet, substantially as set forth.

2. In a telephone-receiver, the combination with a case and the bobbin within the diaphragm-bearing portion of the case and having a head; of devices straddling the head at the latters surrounding edge and'at suitable intervals along the said edge, which headstraddling devices have members or portions thereof overlapping 4opposite sides or faces of the head and are supported from the case, and shiftable, as required, to adjust the bobbin relative to the diaphragm.

3. In a telephone-receiver, in combination with the case and bobbin within the diaphragm-bearing portion of the case and having a head, of screws having shoulders engaging or overlapping opposite sides, respectively, of the said head and screwed into the case, substantially as set forth.

4. In a telephone-receiver, in combination with the case and bobbin within thecase, and having a head provided in its surrounding edge with recesses arranged at suitable intervals, of screws extending through the said recesses into the case, and each screw having shoulders overlapping opposite sides,respeetively, of the head, substantially as set forth.

Signed by me at Cleveland, Ohio, this 5th day of April, 1898.

JOSEPH A. XVILLIAMS.

Vitnesses:

C. H. DoRER, ANNA PARRETT.

however, extend to the narrower or magnetlOO 

